氣喘病是一種慢性支氣管發炎，氣喘發生在臨床上有許多特徵，就肺音訊號而言，哮鳴音為最典型的氣喘發作特徵，另外肺音頻率的變化也是一個相當重要的參考指標。 本篇論文的研究目的，主要是發展一個氣喘肺音監測系統，系統硬體設計包含電容式麥克風的聽診頭、肺音放大濾波電路，資料擷取系統及dsPIC微處理器的警報系統；軟體設計則利用Matlab撰寫監測演算系統，利用C語言撰寫dsPIC微處理器，另外使用者介面使用Matlab圖控人機介面(GUI)，分析方法利用快速傅立葉轉換(FFT)、時頻譜圖(Spectrogram)為基礎作為哮鳴音偵測方法。 氣喘肺音監測利用估算哮鳴音發生的時間及肺音中心能量的頻率來作為觀測氣喘病患的參數，我們設計以10秒擷取肺音一次，並即時計算出參數值，當有異常狀況時可即時發出警報，並可將各項參數及肺音儲存於電腦中，可全天候作偵測監控，監測的參數及肺音也可提供醫師作診斷的判斷。由現階段的發展我們可以正確的區分出正常肺音與哮鳴音，並利用評估參數值而判定氣喘病患的發病狀況。在未來若想由肺音去預警氣喘的發作則需作臨床氣喘肺音及流量值的收集分析，才能做進一步的研究。 Asthma is a chronic bronchus inflammation. In the clinical, there are many characteristics during asthmatic attack. As per lung sound, wheezing is a common clinical finding in patient with asthma. Also, the change of the frequency is an important index. In this thesis, developing an asthma monitoring system based on auscultating lung sound is the principal purpose. The hardware and software are involved in the asthma monitoring system as follows. The hardware includes microphone with stethoscope bell、amplifier、filter、data acquisition device and microprocessor. The software includes Matlab for monitoring analysis、C language for microprocessor and graphical user interface (GUI) developed by Matlab. The power spectrum of lung sound is analyzed by FFT. Base on time-frequency transform by spectrogram is the analyzable method for the wheezing. Proportion of the respiratory cycle occupied by wheeze (Tw/Ttot) and central frequency (Fc) are two index parameters in the asthma monitoring system. The lung sound is got ever ten minutes and parameters are saved in the computer. This system can automatically locate and identify the wheeze signal pattern form lung sound. For physician, they can diagnosis asthmatic patients by record of the parameters and lung sound from the system. For asthmatic patients, the system will give an monitoring alarm under the uncommon condition. The conclusion of the system in the thesis, it is useful for the dividing under uncommon wheeze then alerting from the system. However, pre-alerting for initial asthmatic attack based on lung sound should be furthered researching the relationship between flow and lung sound from asthmatic patient in the future.
